Outline SkImageFilter Make methods

src/effects/SkBlurImageFilter.cpp

 /*
  * Copyright 2011 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBlurImageFilter.h"
 
 #include "SkAutoPixmapStorage.h"
 #include "SkColorPriv.h"
 #include "SkGpuBlurUtils.h"
 #include "SkOpts.h"
 #include "SkReadBuffer.h"
 #include "SkSpecialImage.h"
 #include "SkWriteBuffer.h"
 
 #if SK_SUPPORT_GPU
 #include "GrContext.h"
 #include "SkGr.h"
 #endif
 
+sk_sp<SkImageFilter> SkBlurImageFilter::Make(SkScalar sigmaX, SkScalar sigmaY, 
+                                             sk_sp<SkImageFilter> input,
+                                             const CropRect* cropRect) {
+    if (0 == sigmaX && 0 == sigmaY && !cropRect) {
+        return input;
+    }
+    return sk_sp<SkImageFilter>(new SkBlurImageFilter(sigmaX, sigmaY, input, cropRect));
+}
+
 // This rather arbitrary-looking value results in a maximum box blur kernel size
 // of 1000 pixels on the raster path, which matches the WebKit and Firefox
 // implementations. Since the GPU path does not compute a box blur, putting
 // the limit on sigma ensures consistent behaviour between the GPU and
 // raster paths.
 #define MAX_SIGMA SkIntToScalar(532)
 
 static SkVector map_sigma(const SkSize& localSigma, const SkMatrix& ctm) {
     SkVector sigma = SkVector::Make(localSigma.width(), localSigma.height());
     ctm.mapVectors(&sigma, 1);
@@ skipping 209 matching lines @@
     str->appendf("SkBlurImageFilter: (");
     str->appendf("sigma: (%f, %f) input (", fSigma.fWidth, fSigma.fHeight);
 
     if (this->getInput(0)) {
         this->getInput(0)->toString(str);
     }
 
     str->append("))");
 }
 #endif